DES MOINES, Iowa (AP) _ Optimum Quality Grains, a joint venture between Pioneer Hi-Bred International and chemical giant DuPont will be directed by a DuPont executive, the companies said Wednesday.

D.L. ``Dick'' Reasons has held several positions with DuPont in the United States, Europe, Asia and Canada, most recently as chief executive officer of DuPont Quality Grains.

DuPont paid $1.7 billion for a 20 perceake in the Des Moines-based Pioneer, which faces a growing threat from competitors in the corn seed industry it dominates. The companies will work together on crop research.

The deal, announced in early August, was completed Monday.

Under the agreement, the Wilmington, Del.-based DuPont acquired 20 percent of Pioneer's stock for $104 dollars per share, with Pioneer using the proceeds to buy back its own stock. DuPont also gains two of the 15 seats on Pioneer's board of directors.